Lens barrel

ABSTRACT

At an inner circumferential surface of a cam frame, second cam grooves and an inner gear are formed. A second lens group frame includes a base, extensions each extending from the base in an optical axis direction, and cam pins each outwardly protruding from a tip end part of a corresponding one of the extensions in a radial direction. In the extension, a stepped part is formed. The stepped part overlaps, when each cam pin moves according to a corresponding one of the second cam grooves, with the inner gear as viewed in the radial direction, and is recessed toward the inside in the radial direction as compared to a tooth tip of the inner gear so as not to overlap with the tooth tip of the inner gear as viewed in a circumferential direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of International Application No.PCT/JP2012/003857 filed on Jun. 13, 2012, which claims priority toJapanese Patent Application No. 2011-184076 filed on Aug. 25, 2011. Theentire disclosures of these applications are incorporated by referenceherein.

BACKGROUND

The technique disclosed herein relates to a lens barrel.

Conventionally, a lens barrel has been configured such that aframe-shaped member or a cylindrical member configured to directly orindirectly hold a lens(es) moves in an optical axis direction to movethe lens(es) in the optical axis direction.

In each of lens barrels described in Japanese Unexamined PatentPublication No. 2010-186192 and Japanese Unexamined Patent PublicationNo. 2010-204563, a gear part is formed at a rear end of an outercircumferential surface of a drive frame formed with cam grooves. Thegear part of the drive frame is engaged with a drive gear of a fixedframe. In such a state, when a zoom motor is operated, drive force ofthe zoom motor is transmitted to the gear part of the drive framethrough the drive gear. As a result, the drive frame is rotatablydriven. While the drive frame is rotating relative to the fixed frameand is moving in an optical axis direction, a lens(es) is moving in theoptical axis direction.

SUMMARY

However, in each of the lens barrels described in Japanese UnexaminedPatent Publication No. 2010-186192 and Japanese Unexamined PatentPublication No. 2010-204563, a gear serving as the gear part is formedat the outer circumferential surface of the drive frame, and therefore adrive gear of the zoom motor should be disposed outside the drive framein a radial direction. In this configuration, the outer diameter of thelens barrel increases, and it is difficult to reduce the size of thelens barrel.

The technique disclosed herein has been made in view of the foregoing,and aims to devise arrangement of a gear of a cam frame to provide alens barrel having a reduced size.

A lens barrel disclosed herein is a lens barrel in which a lens ismovable in an optical axis direction. The lens barrel includes acylindrical cam frame formed, at an inner circumferential surfacethereof, with a cam groove extending in a predetermined pattern, and aninner gear inwardly protruding in a radial direction and extending in acircumferential direction; and a lens frame including a base configuredto hold the lens inside the cam frame, an extension extending from thebase in the optical axis direction, and a cam pin outwardly protrudingfrom a tip end part of the extension in the radial direction and fittedinto the cam groove. A stepped part which, when the cam pin movesaccording to the cam groove, overlaps with the inner gear as viewed inthe radial direction and is recessed toward an inside in the radialdirection as compared to a tooth tip of the inner gear so as not tocontact the inner gear is provided in the extension.

According to the lens barrel, since the inner gear is formed on theinner circumferential side of the cam frame, the size of the lens barrelcan be reduced as compared to the case where the gear is formed at theouter circumferential surface of the cam frame. Moreover, since theinner gear does not contact the extension of the lens frame when the campin moves according to the cam groove, the lens frame can smoothly movein the optical axis direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an imaging apparatus of an embodiment.

FIG. 2 is a perspective view of a camera body from which a lens barrelis detached.

FIG. 3 is an oblique perspective view of the lens barrel from the front.

FIG. 4 is an oblique perspective view of the lens barrel from the rear.

FIG. 5 is an exploded perspective view of the lens barrel.

FIG. 6 is a longitudinal sectional view of the lens barrel in acollapsed state.

FIG. 7 is a longitudinal sectional view of the lens barrel at awide-angle end thereof.

FIG. 8 is a longitudinal sectional view of the lens barrel at atelephoto end thereof.

FIG. 9 is a perspective view of a lens mount.

FIG. 10 is a side view of the lens barrel.

FIG. 11 is an exploded perspective view of an outer frame.

FIG. 12 is a rear view of the lens barrel in the state in which the lensmount is detached.

FIG. 13 is a schematic view illustrating the configuration of a zoomlever switch.

FIG. 14 is a side view of an assembly of the zoom lever switch, a focuslever switch, and a flexible printed circuit board, and corresponds toFIG. 10.

FIG. 15 is an exploded view of a cam frame when an inner circumferentialsurface of the cam frame is viewed from an inner circumferential side.

FIG. 16 is an oblique perspective view of a second lens group frame andthe cam frame from the front.

FIG. 17 is an enlarged longitudinal sectional view of part of the secondlens group frame and part of the cam frame.

FIG. 18 is an oblique perspective view of a fifth lens group frame fromthe front.

FIG. 19 is a perspective view illustrating the configuration of theflexible printed circuit board.

FIG. 20 is a rear view of the lens barrel in the state in which the lensmount is detached.

FIG. 21 is an exploded view of an assembly of first to fourth molds whenan inner circumferential surface thereof is viewed from an innercircumferential side.

FIG. 22 is a longitudinal sectional view illustrating the state in whichthe first to fourth molds and a base mold are assembled together.

FIG. 23 is a longitudinal sectional view illustrating the state in whichthe first to fourth molds and the base mold are removed.

DETAILED DESCRIPTION

Embodiments are described in detail below with reference to the attacheddrawings. However, unnecessarily detailed description may be omitted.For example, detailed description of well known techniques ordescription of the substantially same elements may be omitted. Suchomission is intended to prevent the following description from beingunnecessarily redundant and to help those skilled in the art easilyunderstand it.

Inventor(s) provides the following description and the attached drawingsto enable those skilled in the art to fully understand the presentdisclosure. Thus, the description and the drawings are not intended tolimit the scope of the subject matter defined in the claims.

An example embodiment will be described in detail below with referenceto drawings.

<1. Schematic Configuration of Imaging Apparatus>

FIG. 1 is a perspective view of an imaging apparatus 1. The imagingapparatus 1 is a digital camera with interchangeable lenses. The imagingapparatus 1 includes a camera body 2 and a lens barrel 3 detachablyattached to the camera body 2. In the present embodiment, a side closeto an object in an optical axis direction of the lens barrel 3 is, forthe sake of simplicity, referred to as a “front,” and a side close tothe camera body in the optical axis direction is referred to as a“rear.” Moreover, a right side as viewed from the side close to theobject in the optical axis direction is referred to as a “right,” and aleft side as viewed from the side close to the object in the opticalaxis direction is referred to as a “left.” Unless otherwise described, a“circumferential direction” means a circumferential direction about anoptical axis, and a “radial direction” means a radial direction aboutthe optical axis.

FIG. 2 is a perspective view of the camera body 2 from which the lensbarrel 3 is detached. The camera body 2 includes a body mount 2 a towhich the lens barrel 3 is attached, an imaging device 2 b configured tocapture an optical image formed by the lens barrel 3 to convert theoptical image into image data, and a shutter button 2 c. The shutterbutton 2 c is provided on an upper left end part of the camera body 2.

<2-1. Configuration of Lens Barrel>

FIG. 3 is an oblique perspective view of the lens barrel 3 from thefront. FIG. 4 is an oblique perspective view of the lens barrel 3 fromthe rear. FIG. 5 is an exploded perspective view of the lens barrel 3.FIG. 6 is a longitudinal sectional view of the lens barrel 3 in acollapsed state. FIG. 7 is a longitudinal sectional view of the lensbarrel 3 at a wide-angle end thereof. FIG. 8 is a longitudinal sectionalview of the lens barrel 3 at a telephoto end thereof.

The lens barrel 3 is a collapsible zoom lens barrel. Referring to FIG.3, the lens barrel 3 includes a barrel body 3A, a zoom lever switch 73,and a focus lever switch 74. The zoom lever switch 73 and the focuslever switch are provided on the barrel body 3A. The zoom lever switch73 is an operation section operated by a user to adjust themagnification of an optical system L, and serves as a “zoom operationsection” configured to transmit a user's operation instruction to a zoomadjustment mechanism which will be described later. The focus leverswitch 74 is an operation section operated by the user to adjust thefocus of the optical system L, and serves as a “focus operation section”configured to transmit a user's operation instruction to a focusadjustment mechanism which will be described later. Although will bedescribed in detail later, a bayonet lens mount 90 is, referring to FIG.4, provided at a rear end of the lens barrel 3. The lens barrel 3 ismechanically and electrically connected to the camera body 2 through thelens mount 90 and the body mount 2 a.

Referring to FIG. 5, the barrel body 3A includes the optical system L(see FIGS. 6-8) including a plurality of lenses, a plurality of lensframes 10-50 each configured to hold the lens(es), a cam frame 60configured to transmit drive force to the lens frames 10-50, an outerframe 70 in which the lens frames 10-50 and the cam frame 60 are housed,a printed circuit board 80 (illustrated only in FIG. 12), and the lensmount 90.

Specifically, the optical system L is, referring to FIGS. 6-8, a zoomlens system configured to form an optical image of the object, andincludes first to fifth lens groups G1-G5. The first lens group G1includes first to third lenses L1-L3. The second lens group G2 includesfourth to sixth lenses L4-L6. The third lens group G3 includes a seventhlens L7. The lenses of the first to third lens groups G1-G3 are zoomlenses. The lens of the third lens group G3 also functions as a lens forimage blur correction. The fourth lens group G4 includes an eighth lensL8. The lens of the fourth lens group G4 is a focus lens. The fifth lensgroup G5 includes a ninth lens L9.

The outer frame 70 is a cylindrical component. A plurality of camgrooves 71 each extending in a predetermined pattern and a plurality oftranslational grooves 72 each extending in the optical axis directionare formed at an inner circumferential surface of the outer frame 70.The outer frame 70 serves as an exterior part of the lens barrel 3exposed to the outside.

In the printed circuit board 80, at least a lens microcomputer (notshown in the figure) and a memory (not shown in the figure) areprovided. Electric components of the lens barrel 3 are electricallyconnected to the printed circuit board 80 through flexible printedcircuit boards. The printed circuit board 80 is also electricallyconnected to a mount contact (not shown in the figure) provided in thelens mount 90. That is, the printed circuit board 80 is electricallyconnected to the camera body 2 when the lens barrel 3 is attached to thecamera body 2. The printed circuit board 80 is disposed between thefifth lens group frame 50 and the lens mount 90.

The lens mount 90 is a circular component formed with an opening at thecenter thereof, and is attachable to the body mount 2 a. The position ofthe lens barrel 3 relative to the camera body 2 is determined with thelens mount 90 contacting the camera body 2. The lens mount 90 isattached to a rear end surface of the outer frame 70 through screws 91.

The cam frame 60 is a cylindrical component. A plurality of first camgrooves 61 each extending in a predetermined pattern and a plurality ofcam pins 63 each outwardly protruding from a rear end part of the camframe 60 are formed at an outer circumferential surface of the cam frame60. Moreover, a plurality of second cam grooves 62 each extending in apredetermined pattern and an inner gear 64 (see FIG. 5) are formed at aninner circumferential surface of the cam frame 60. The inner gear 64 isformed between adjacent ones of the second cam grooves 62 so as toextend in the circumferential direction.

The first lens group frame 10 is a cylindrical component, and isconfigured to hold the first lens group G1. A plurality of protrusions11 each outwardly protruding from a rear end part of the first lensgroup frame 10 are formed at an outer circumferential surface of thefirst lens group frame 10. A plurality of translational grooves 12 eachextending in the optical axis direction and a plurality of cam pins 13each inwardly protruding from the rear end part of the first lens groupframe 10 are formed at an inner circumferential surface of the firstlens group frame 10.

The second lens group frame 20 is a circular component formed with anopening at the center thereof, and is configured to hold the second lensgroup G2 at the opening of the second lens group frame 20. In the secondlens group frame 20, a plurality of protrusions 21 each outwardlyprotruding from a front end part of the second lens group frame 20 and aplurality of cam pins 22 each outwardly protruding from a rear end partof the second lens group frame 20 are provided. In the second lens groupframe 20, two coils 23 are provided respectively at positions eachfacing a corresponding one of two magnets 31 (described later) of thethird lens group frame 30. A diaphragm mechanism 24 is provided in thesecond lens group frame 20.

The third lens group frame 30 is a circular component formed with anopening at the center thereof, and is configured to hold the third lensgroup G3 at the opening of the third lens group frame 30. The third lensgroup frame 30 is held at a rear surface of the second lens group frame20 so as to move in a plane perpendicular to an optical axis AX. The twomagnets 31 are provided in the third lens group frame 30. The third lensgroup frame 30 is driven by magnetic force generated by the coils 23 ofthe second lens group frame 20 to move in the plane perpendicular to theoptical axis AX.

The first and third lens group frames 10-30 and the cam frame 60 areintegrally incorporated into the outer frame 70. Specifically, the camframe 60 is housed in the first lens group frame 10. In such a state,each cam pin 13 of the first lens group frame 10 is fitted into acorresponding one of the first cam grooves 61 of the cam frame 60.Moreover, each cam pin 63 of the cam frame 60 outwardly protrudesrelative to the first lens group frame 10 at the rear of the first lensgroup frame 10. The second lens group frame 20 is housed in the camframe 60. In such a state, each cam pin 22 is fitted into acorresponding one of the second cam grooves 62 of the cam frame 60. Eachprotrusion 21 outwardly protrudes relative to the cam frame 60 at thefront of the cam frame 60, and is fitted into a corresponding one of thetranslational grooves 12 of the first lens group frame 10. The firstlens group frame 10 is housed in the outer frame 70. In such a state,each protrusion 11 is fitted into a corresponding one of thetranslational grooves 72 of the outer frame 70. Moreover, each cam pin63 of the cam frame 60 outwardly protruding relative to the first lensgroup frame 10 is fitted into a corresponding one of the cam grooves 71of the outer frame 70.

The fifth lens group frame 50 is a circular component formed with anopening at the center thereof, and is configured to hold the fifth lensgroup G5 at the opening of the fifth lens group frame 50. The fifth lensgroup frame 50 is, at a rear end surface thereof, attached to the outerframe 70 through screws. Two shafts 51 each extending toward the frontin the optical axis direction inside the outer frame 70 are provided inthe fifth lens group frame 50. In the fifth lens group frame 50, a zoommotor 52 configured to drive the cam frame 60 and a focus motor 53 (seeFIGS. 18 and 19) configured to drive the fourth lens group frame 40 areprovided.

A lead screw extending in the optical axis direction is provided in anoutput shaft of the focus motor 53. A drive gear 52 a (see FIGS. 18 and19) rotating about a rotation axis extending in the optical axisdirection is connected to an output shaft of the zoom motor 52 through agear train. The drive gear 52 a is engaged with the inner gear 64 of thecam frame 60. That is, the cam frame 60 is rotatably driven by the zoommotor 52. The zoom motor 52 and the cam frame 60 form the “zoomadjustment mechanism” configured to adjust the magnification of theoptical system L.

The fourth lens group frame 40 is a circular component formed with anopening at the center thereof, and is configured to hold the fourth lensgroup G4 at the opening of the fourth lens group frame 40. The fourthlens group frame 40 is supported through the shafts 51 provided in thefifth lens group frame 50 so as to move in the optical axis direction. Arack is provided in the fourth lens group frame 40, and is engaged withthe lead screw of the focus motor 53. That is, the fourth lens groupframe 40 is driven by the focus motor 53. The focus motor 53 and thefourth lens group frame 40 form the “focus adjustment mechanism”configured to adjust the focus of the optical system L.

<2-2. Operation of Lens Barrel>

In the lens barrel 3 configured as described above, the zoom motor 52rotatably drives the cam frame 60. The rotatably-driven cam frame 60rotates while moving in the optical axis direction according to the camgrooves 71 of the outer frame 70. Each cam pin 13 of the first lensgroup frame 10 is fitted into a corresponding one of the first camgrooves 61 of the cam frame 60, and each protrusion 11 of the first lensgroup frame 10 is fitted into a corresponding one of the translationalgrooves 72 of the outer frame 70 such that the first lens group frame 10does not rotate relative to the outer frame 70. Thus, rotation of thecam frame 60 allows the first lens group frame 10 to move, withoutrotation, in the optical axis direction in accordance with movement ofeach cam pin 13 relative to a corresponding one of the first cam grooves61. Each cam pin 22 of the second lens group frame 20 is fitted into acorresponding one of the second cam grooves 62 of the cam frame 60, andeach protrusion 21 of the second lens group frame 20 is fitted into acorresponding one of the translational grooves 12 of the first lensgroup frame 10 such that the second lens group frame 20 does not rotaterelative to the first lens group frame 10. Thus, rotation of the camframe 60 allows the second lens group frame 20 to move, withoutrotation, in the optical axis direction in accordance with movement ofeach cam pin 22 relative to a corresponding one of the second camgrooves 62. The third lens group frame 30 moves with the second lensgroup frame 20 in the optical axis direction. The first to third lensgroup frames 10-30 move in the optical axis direction in this manner,thereby adjusting the magnification of the optical system L of the lensbarrel 3. The third lens group frame 30 is driven by the coils 23 tomove in the plane perpendicular to the optical axis AX, therebycorrecting an image blur. The fourth lens group frame 40 is,independently of the first to third lens group frames 10-30, driven bythe focus motor 53 to move in the optical axis direction. In thismanner, the focus of the lens barrel 3 is adjusted.

More specifically, when the lens barrel 3 is powered off, the first tothird lens group frames 10-30 are at a collapsed position illustrated inFIG. 6. When the lens barrel 3 is powered on, the first to third lensgroup frames 10-30 move from the collapsed position to the wide-angleend illustrated in FIG. 7. Then, when the user operates the zoom leverswitch 73, a signal corresponding to an operation amount is input to thelens microcomputer of the printed circuit board 80. The lensmicrocomputer outputs a drive signal corresponding to the input signalto the zoom motor 52. The zoom motor 52 is operated in response to thedrive signal to rotatably drive the cam frame 60. As a result, the firstto third lens group frames 10-30 move in the optical axis directionbetween the wide-angle end and the telephoto end illustrated in FIG. 8.In this manner, zoom magnification is manually adjusted.

In such a state, the fourth lens group frame 40 is driven in tandem withthe first to third lens group frames 10-30. Specifically, the lensmicrocomputer moves, based on a pre-stored tracking table, the fourthlens group frame 40 to the position at which a focus state can bemaintained before and after a change in magnification of the opticalsystem L. That is, upon receipt of the input signal, the lensmicrocomputer outputs the drive signal not only to the zoom motor 52,but also to the focus motor 53. As a result, the fourth lens group frame40 moves corresponding to the first to third lens group frames 10-30.Note that the user can operate the focus lever switch 74 to manuallyadjust the position of the fourth lens group frame 40. Specifically,when the focus lever switch 74 is operated, a signal corresponding to anoperation amount is input to the lens microcomputer of the printedcircuit board 80. The lens microcomputer outputs a drive signalcorresponding to the input signal to the focus motor 53. The focus motor53 is operated in response to the drive signal to move the fourth lensgroup frame 40 in the optical axis direction. In this manner, the focusstate is manually adjusted.

<2-3. Specific Configuration of Lens Mount>

FIG. 9 is a perspective view of the lens mount 90.

First, the configuration of the lens mount 90 at a front surface thereofwill be described. The lens mount 90 is, at the front surface thereof,in a stepped shape formed of an attachment surface 92 which is formed ata circumferential edge of the lens mount 90 and a recessed part 93 whichis part of the lens mount 90 inside the attachment surface 92 in theradial direction and which is recessed toward the rear. The attachmentsurface 92 is for attachment of the outer frame 70, and the lens mount90 is screwed to the outer frame 70 with the attachment surface 92contacting the rear end surface of the outer frame 70. The recessed part93 is part of the lens mount 90 facing a rear end surface of the firstlens group frame 10 and a rear end surface of the cam frame 60. In thecollapsed state, the rear end parts of the first lens group frame 10 andthe cam frame 60 are positioned on the rear side relative to theattachment surface 92, and enter the recessed part 93. Note that, evenin the collapsed state in which the first lens group frame 10 and thecam frame 60 are at the rearmost position, the rear end surfaces of thefirst lens group frame 10 and the cam frame 60 do not contact therecessed part 93. At a circumferential part of the recessed part 93 onthe inside in the radial direction, a protrusion 93 a slightlyprojecting toward the front than the other part of the recessed part 93is formed. The protrusion 93 a does not face the rear end surfaces ofthe first lens group frame 10 and the cam frame 60, and is positionedinside such rear end surfaces in the radial direction. Part of the lensmount 90 inside the recessed part 93 in the radial direction is furtherrecessed toward the rear, and a plurality of steps are formed in such apart. An opening 90 a is formed at the center of the lens mount 90.

Referring to FIGS. 4 and 6-8, the lens mount 90 is, at part of a rearsurface corresponding to the attachment surface 92 and the recessed part93, not in a stepped shape, but forms a tapered surface 94. Thus, thethickness T1 of part 90A of the attachment surface 92 of the lens mount90 is, in part, greater than the thickness T2 of part 90B of therecessed part 93. Note that insertion holes into each of which acorresponding one of the screws 91 is inserted are formed in the lensmount 90, and a counterbore is formed at part of the tapered surface 94corresponding to each insertion hole. Although the tapered surface 94 isformed in this example, the tapered surface 94 is not necessarilyformed. In such a case, the thickness of the entirety of the part 90A ofthe attachment surface 92 is greater than that of the part 90B of therecessed part 93.

<3. Specific Configuration of Lever Switch>

The specific configuration of the zoom lever switch 73 and the focuslever switch 74 will be described below. FIG. 10 is a side view of thelens barrel 3. FIG. 11 is an exploded perspective view of the outerframe 70. FIG. 12 is a rear view of the lens barrel 3 in the state inwhich the lens mount 90 is detached. FIG. 13 is a schematic viewillustrating the configuration of the zoom lever switch 73 and the focuslever switch 74.

The zoom lever switch 73 and the focus lever switch 74 are arranged onan outer circumferential surface of the outer frame 70. A rectangularopening 70 a is formed at the outer circumferential surface of the outerframe 70, and the zoom lever switch 73 and the focus lever switch 74 arearranged inside the opening 70 a.

The zoom lever switch 73 and the focus lever switch 74 are arranged inthe circumferential direction about the optical axis AX. The arrangementin the circumferential direction means that the positions in thecircumferential direction about the optical axis AX are different fromeach other and the positions in the optical axis direction at leastpartially overlap with each other. In other words, the zoom lever switch73 and the focus lever switch 74 are provided on the same circle. In thepresent embodiment, the positions of the zoom lever switch 73 and thefocus lever switch 74 in the circumferential direction are differentfrom each other, and the positions of the zoom lever switch 73 and thefocus lever switch 74 in the optical axis direction are completelycoincident with each other.

Specifically, the zoom lever switch 73 and the focus lever switch 74are, referring to FIG. 12, arranged within an arrangement region A ofthe outer frame 70. The arrangement region A is a region on the rightrelative to the optical axis AX as viewed from the side close to theobject in the optical axis direction, i.e., a region formed of a firstquadrant Q1 and a fourth quadrant Q4 of the outer frame 70. Suppose thatthe lens barrel 3 attached to the camera body 2 in a horizontal attitudeis, as viewed from the side close to object in the optical axisdirection, divided into four regions by vertical and horizontal axesperpendicular to the optical axis AX. An upper right region is a firstquadrant, an upper left region is a second quadrant, a lower left regionis a third quadrant, and a lower right region is a fourth quadrant. The“horizontal attitude” means the attitude or state in which ahorizontally-long image can be shot by the camera body 2. On the otherhand, the attitude or state in which a vertically-long image can be shotby the camera body 2 is referred to as a “vertical attitude.” Morespecifically, the zoom lever switch 73 is disposed in the first quadrantQ1, and the focus lever switch 74 is disposed in the fourth quadrant Q4.In the state in which the switch is disposed in a certain region such asthe arrangement region A, the first quadrant Q1, or the fourth quadrantQ4, at least part of the switch may be within such a region, and theentirety of the switch is not necessarily positioned within the region.

Referring to FIG. 13, the zoom lever switch 73 is a momentary (i.e.,self-restoring) switch, and includes a switch body 73A and a zoom switchsupport 75 c.

The switch body 73A includes a lever 73 a, a resistor member 73 b, andtwo springs 73 c. The lever 73 a includes a plate-shaped lever base 73 dextending in the circumferential direction about the optical axis AX, anoperating section 73 e outwardly protruding from the lever base 73 d inthe radial direction, and a contact 73 f inwardly protruding from thelever base 73 d in the radial direction. Part of the lever 73 a otherthan the contact 73 f is made of resin. The contact 73 f is made of aconductive material. A tip end surface of the operating section 73 e isin a substantially rectangular shape. Knurls are formed at the tip endsurface of the operating section 73 e. The lever 73 a is supported bythe outer frame 70 so as to slide in the circumferential direction. Thelever 73 a is biased toward one side in the circumferential direction byone of the springs 73 c, and is biased toward the other side in thecircumferential direction by the other spring 73 c. The lever 73 a isnormally (i.e., when the lever 73 a is not operated by the user) at theposition (hereinafter referred to as a “reference position”) at whichbiasing force is balanced between the two springs 73 c. The user appliesexternal force to the lever 73 a to move the lever 73 a in thecircumferential direction against biasing force of the springs 73 c.When the user releases the external force, the lever 73 a returns to thereference position by biasing force of the springs 73 c. That is, thelever 73 a is elastically supported, and is operable against elasticforce. In such a state, the contact 73 f contacts the resistor member 73b, and is electrically connected to the resistor member 73 b. A contactposition between the resistor member 73 b and the contact 73 f moves inaccordance with movement of the lever 73 a. That is, a resistance valuebetween a terminal connected to the contact 73 f and a terminalconnected to the resistor member 73 b is detected as the operationamount of the lever 73 a. The rotation speed of the zoom motor isdetermined based on the resistance value. That is, the drive signal isinput from the lens microcomputer to the zoom motor such that the zoommotor rotates at a rotation speed corresponding to the resistance value.

A zoom switch opening 75 a is formed in the zoom switch support 75 c.The zoom switch support 75 c closes the opening 70 a of the outer frame70, and exposes, through the zoom switch opening 75 a, the operatingsection 73 e of the zoom lever switch 73 to the outside. The zoom switchsupport 75 c is raised toward the outside in the radial directionrelative to the outer circumferential surface of the outer frame 70.

The basic configuration of the focus lever switch 74 is similar to thatof the zoom lever switch 73. As well as the zoom lever switch 73, thefocus lever switch 74 is a momentary (i.e., self-restoring) switch, andincludes a switch body 74A and a focus switch support 75 d.

The switch body 74A includes a lever 74 a, a resistor member 74 b, andtwo springs 74 c. The switch body 74A includes a lever base 74 d, anoperating section 74 e, and a contact 74 f. The lever 74 a iselastically supported by the springs 74 c, and is operable againstelastic force. Knurls are formed at a tip end surface of the operatingsection 74 e. A resistance value between a terminal connected to thecontact 74 f and a terminal connected to the resistor member 74 b isdetected as the operation amount of the lever 74 a. The rotation speedof the focus motor 53 is determined based on the resistance value. Thatis, the drive signal is input from the lens microcomputer to the focusmotor 53 such that the focus motor 53 rotates at a rotation speedcorresponding to the resistance value.

A focus switch opening 75 b is formed in the focus switch support 75 d.The focus switch support 75 d closes the opening 70 a of the outer frame70, and exposes, through the focus switch opening 75 b, the operatingsection 74 e of the focus lever switch 74 to the outside. The focusswitch support 75 d is raised toward the outside in the radial directionrelative to the outer circumferential surface of the outer frame 70.

The zoom switch support 75 c and the focus switch support 75 d areintegrally formed, and form a cover 75.

The zoom lever switch 73 and the focus lever switch 74 are configuredsuch that a shape varies between the zoom lever switch 73 and the focuslever switch 74.

Specifically, the zoom lever switch 73 and the focus lever switch 74 areformed such that the height H1a of the operating section 73 e and theheight H1b of the operating section 74 e are different from each other.The “height H” means the amount of protrusion from the outercircumferential surface of the outer frame 70 to the outside in theradial direction. More specifically, the operating section 73 e of thezoom lever switch 73 is higher than the operating section 74 e of thefocus lever switch 74. The zoom lever switch 73 and the focus leverswitch 74 are formed such that the width W1a of the operating section 73e in the circumferential direction and the width W1b of the operatingsection 74 e in the circumferential direction are different from eachother. Specifically, the width W1a of the operating section 73 e of thezoom lever switch 73 in the circumferential direction is greater thanthe width W1b of the operating section 74 e of the focus lever switch 74in the circumferential direction.

The zoom lever switch 73 and the focus lever switch 74 are formed suchthat the width W2a of the zoom switch support 75 c in thecircumferential direction and the width W2b of the focus switch support75 d in the circumferential direction are different from each other.Specifically, the width W2a of the zoom switch support 75 c in thecircumferential direction is greater than the width W2b of the focusswitch support 75 d in the circumferential direction.

<4. Wiring of Lever Switch>

Next, wiring of the zoom lever switch 73 and the focus lever switch 74will be described. FIG. 14 is a side view of an assembly of the zoomlever switch 73, the focus lever switch 74, and a flexible printedcircuit board, and corresponds to FIG. 10.

The zoom lever switch 73 and the focus lever switch 74 are arrangedadjacent to each other, and specifically arranged adjacent to each otherin the circumferential direction. Thus, the same flexible printedcircuit board 81 is connected to the zoom lever switch 73 and the focuslever switch 74. That is, the zoom lever switch 73 and the focus leverswitch 74 are electrically connected to a single flexible printedcircuit board 81. Specifically, the focus lever switch 74 and the zoomlever switch 73 are electrically connected to the flexible printedcircuit board 81 in this order from one end side of the flexible printedcircuit board 81. The flexible printed circuit board 81 slightly extendsfrom the zoom lever switch 73 in the circumferential direction, and isbent toward the rear.

Referring to FIG. 12, the fifth lens group frame 50 is disposed insidethe outer frame 70, and the printed circuit board 80 is disposed at therear of the fifth lens group frame 50. Flexible printed circuit boardsare drawn from various components of the lens barrel 3 to the rear sideof the printed circuit board 80. For example, a flexible printed circuitboard 82 is drawn from the zoom motor 52 to the rear side of the printedcircuit board 80, and a flexible printed circuit board 83 is drawn fromthe focus motor 53 to the rear side of the printed circuit board 80. Theflexible printed circuit board 83 is, at one end thereof, connected to aconnector 84 of the printed circuit board 80. A first connector 83 a anda second connector 83 b are provided on the flexible printed circuitboard 83. The flexible printed circuit board 81 is, at one end thereof,connected to the first connector 83 a. The flexible printed circuitboard 82 is, at one end thereof, connected to the second connector 83 b.That is, the flexible printed circuit board 81 and the flexible printedcircuit board 82 are joined to the flexible printed circuit board 83,and therefore are connected to the printed circuit board 80 through theflexible printed circuit board 83.

<5. Operation of Lever Switch>

Operation of the lever switches will be described below.

Referring to FIG. 1, the shutter button 2 c is provided on an upper leftsurface of the camera body 2 as viewed from the side close to the objectin the optical axis direction. In the case where the user holds theimaging apparatus 1 in the horizontal attitude, the imaging apparatus 1is held with a right index finger being placed on the shutter button 2c. In such a state, a left hand is normally placed on the lens barrel 3such that an index finger is positioned substantially in the thirdquadrant of the lens barrel 3 and that a thumb is positioned in thefourth or first quadrant of the lens barrel 3.

On the other hand, in the case where the imaging apparatus 1 is in thevertical attitude, the imaging apparatus 1 is often held such that theshutter button 2 c is positioned on the upper side, and a right hand isplaced on the upper side. Moreover, the left hand is often placed on thelens barrel 3 such that the index finger is positioned substantially inthe fourth quadrant of the lens barrel 3 and that the thumb ispositioned in the first or second quadrant of the lens barrel 3.

Regardless of whether the imaging apparatus 1 is in the horizontalattitude or the vertical attitude, any of the index finger and the thumbof the left hand is positioned in the arrangement region A formed of thefirst and fourth quadrants of the lens barrel 3. In the arrangementregion A, the zoom lever switch 73 and the focus lever switch 74 arepositioned. Thus, the user operates, with his index finger or thumb, thezoom lever switch 73 and the focus lever switch 74 in the state in whichthe left hand is effortlessly placed on the lens barrel 3.

When the zoom lever switch 73 and the focus lever switch 74 areoperated, the user views the object through a finder or a liquid crystalscreen of the camera body 2, and does not operate the zoom lever switch73 and the focus lever switch 74 while looking the zoom lever switch 73and the focus lever switch 74. For such a reason, there is a possibilitythat the user is not sure which one of the zoom lever switch 73 or thefocus lever switch 74 is operated. As described above, the zoom leverswitch 73 and the focus lever switch 74 are formed in the differentshapes. Thus, by touching the switch, the user can identify, withoutlooking, whether the switch to be operated is the zoom lever switch 73or the focus lever switch 74.

<6. Specific Structure of Cam Frame and Second Lens Group Frame>

FIG. 15 is an exploded view of the cam frame when the innercircumferential surface thereof is viewed from an inner circumferentialside. FIG. 16 is an oblique perspective view of the second lens groupframe and the cam frame from the front. FIG. 17 is an enlargedlongitudinal sectional view of part of the second lens group frame andpart of the cam frame. FIG. 18 is an oblique perspective view of thefifth lens group frame from the front.

FIG. 15 is the exploded view of the cam frame 60 when the innercircumferential surface thereof is viewed from the inner circumferentialside. In FIG. 15, an upper side in the plane of paper is the side closeto the object, and a lower side in the plane of paper is the side closeto the camera body. Referring to FIG. 15, the plurality of second camgrooves 62 each extending in the predetermined pattern and the innergear 64 inwardly protruding in the radial direction and extending in thecircumferential direction are formed at the inner circumferentialsurface of the cam frame 60.

Three second cam grooves 62 are formed so as to be apart from each otherin the circumferential direction. Each second cam groove 62 includes afirst circumferential straight part 62 a extending straight toward theright in the circumferential direction at the position close to an upperedge of the cam frame 60, an inclined straight part 62 b extendingstraight from one end of the first circumferential straight part 62 a soas to be inclined relative to the optical axis (i.e., extendingobliquely downward to the right), and a second circumferential straightpart 62 c extending straight from one end of the inclined straight part62 b toward the right in the circumferential direction. A left end partof the first circumferential straight part 62 a communicates with a campin insertion part 62 d downwardly extending from the upper edge of thecam frame 60 along the optical axis.

The inner gear 64 is formed between the inclined straight parts 62 b ofadjacent ones of the second cam grooves 62 so as to extend in thecircumferential direction. The inner gear 64 is, in the optical axisdirection, positioned between the second circumferential straight part62 c of the left one of the second cam grooves 62 and the firstcircumferential straight part 62 a of the right one of the second camgrooves 62. The inner gear 64 includes a plurality of teeth arranged inthe circumferential direction and extending such that edges of the teethare parallel to the optical axis.

As also will be seen from FIG. 16, the second lens group frame 20 is thecircular component formed with an opening at the center thereof. Thesecond lens group frame 20 includes a base 21 a configured to hold thesecond lens group G2 at the opening thereof, the plurality ofprotrusions 21 each outwardly protruding from a front end part of thebase 21 a in the radial direction, a plurality of extensions 21 bprovided so as to be apart from each other in the circumferentialdirection of the base 21 a and each protruding toward the rear from anouter circumferential end part of the base 21 a, and the cam pins 22each outwardly protruding from a tip end part of a corresponding one ofthe extensions 21 b in the radial direction. Each cam pin 22 is fittedinto a corresponding one of the second cam grooves 62 of the cam frame60.

A stepped part 21 c is formed in one of the extensions 21 b (see FIG.17). The stepped part 21 c forms a relief clearance configured to avoidcontact between a tooth tip 64 a of the inner gear 64 and the extension21 b while the cam pin 22 is moving according to the second cam groove62. Specifically, the stepped part 21 c is in a shape inwardly recessedin the radial direction as compared to the tooth tip 64 a of the innergear 64 so as to overlap with the inner gear 64 as viewed in the radialdirection and so as not to overlap with the tooth tip 64 a of the innergear 64 as viewed in the circumferential direction.

<7. Wiring of Motor>

FIG. 19 is a perspective view illustrating the configuration of theflexible printed circuit board. FIG. 20 is a rear view of the lensbarrel in the state in which the lens mount is detached.

Next, wiring of the zoom motor 52 and the focus motor 53 will bedescribed. Referring to FIGS. 19 and 20, the zoom motor 52 and the focusmotor 53 are electrically connected to the single flexible printedcircuit board 83.

Specifically, the flexible printed circuit board 82 is electricallyconnected to the zoom motor 52. The flexible printed circuit board 83 iselectrically connected to the focus motor 53. The flexible printedcircuit boards 82, 83 are drawn to the rear side of the fifth lens groupframe 50.

The printed circuit board 80 is disposed at the rear of the fifth lensgroup frame 50. The flexible printed circuit board 83 is, at one endthereof, connected to the connector 84 of the printed circuit board 80.The first connector 83 a and the second connector 83 b are provided onthe flexible printed circuit board 83.

The flexible printed circuit board 81 is, at one end thereof, connectedto the first connector 83 a. The flexible printed circuit board 81 is,at the other end thereof, electrically connected to the zoom leverswitch 73 and the focus lever switch 74.

The flexible printed circuit board 82 is, at one end thereof, connectedto the second connector 83 b. That is, the flexible printed circuitboards 81, 82 are joined to the flexible printed circuit board 83, andtherefore are connected to the printed circuit board 80 through theflexible printed circuit board 83.

<8. Molds of Cam Frame>

FIG. 21 is an exploded view of an assembly of first to fourth molds whenan inner circumferential surface thereof is viewed from an innercircumferential side. FIG. 22 is a longitudinal sectional viewillustrating the state in which the first to fourth molds and a basemold are assembled together. FIG. 23 is a longitudinal sectional viewillustrating the state in which the first to fourth molds and the basemold are removed. Three second cam grooves 62 and a single inner gear 64are formed at the inner circumferential surface of the cam frame 60.Seven separate molds illustrated in FIG. 21 are used to form the innercircumferential surface of the cam frame 60 by resin molding. Although amold(s) for forming the first cam grooves 61 at the outercircumferential surface of the cam frame 60 is additionally required,the description thereof will not be made below, and only the molds forforming the inner circumferential surface of the cam frame 60 will bedescribed.

Referring to FIG. 21, the molds for forming the inner circumferentialsurface of the cam frame 60 include a first mold 95 configured to formpart of the inner gear 64 and the cam pin insertion part 62 d, a secondmold 96 configured to form the remaining part of the inner gear 64 andpart of the second cam groove 62 positioned on one side (i.e., the upperside as viewed in FIG. 21) relative to the inner gear 64 in the opticalaxis direction, a third mold 97 configured to form the second cam groove62 positioned on the other side (i.e., the lower side as viewed in FIG.21) relative to the inner gear 64 in the optical axis direction, and afourth mold 98 configured to form the second cam groove 62 apart fromthe inner gear 64 in the circumferential direction.

The first mold 95 includes a gear molding part 95 a corresponding topart of the inner gear 64, and a pin insertion molding part 95 bcorresponding to the cam pin insertion part 62 d. The second mold 96includes a gear molding part 95 a corresponding to the remaining part ofthe inner gear 64, and a cam groove molding part 96 a corresponding topart of the second cam groove 62. The third and fourth molds 97, 98 eachinclude a cam groove molding part 96 a corresponding to the second camgroove 62.

A left end edge (i.e., a left end edge of the cam groove molding part 96a) of the first circumferential straight part 62 a of the second camgroove 62 formed using the second mold 96 is a separation line at whichthe first mold 95 and the second mold 96 are separated from each otherin the circumferential direction. That is, part of the inner gear 64 andthe cam pin insertion part 62 d on the left side of the separation lineare formed using the first mold 95. Moreover, the remaining part of theinner gear 64 on the right side of the separation line is formed usingthe second mold 96.

A left end edge (more precisely, a position slightly apart from the leftend edge of the inner gear 64) of the inner gear 64 formed using thefirst mold 95 is a separation line at which the first mold 95 and thethird mold 97 are separated from each other in the circumferentialdirection. A lower end edge of the inner gear 64 formed using the firstmold 95 is a separation line at which the first mold 95 and the secondmold 96 are separated from each other in the optical axis direction andthe first mold 95 and the third mold 97 are separated from each other inthe optical axis direction.

Each of the first to fourth molds 95-98 is formed in an arc shape. Thefirst to fourth molds 95-98 are assembled into a ring-shaped moldillustrated in FIG. 22. The inner circumferential surface of thering-shaped assembly of the first to fourth molds 95-98 forms a taperedshape in which the size of an opening decreases toward the upper side. Aconical base mold 99 is fitted into the ring-shaped assembly of thefirst to fourth molds 95-98 along the inner circumferential surfacethereof. The cam frame 60 is, by resin molding, formed using the firstto fourth molds 95-98, the base mold 99, and otherouter-circumferential-side mold(s) which is not shown in the figure.

After the cam frame 60 is formed by resin molding, the base mold 99 isfirst moved downward and removed as illustrated in FIG. 23. Since thetooth edges of the inner gear 64 extend parallel to the optical axis,the first mold 95 is moved upward and removed. Since the second camgrooves 62 are formed using the second to fourth molds 96-98, the secondto fourth molds 96-98 cannot be moved in the optical axis direction. Forsuch a reason, the second to fourth molds 96-98 are obliquely downwardlymoved toward the inside in the radial direction, and then are removed.In this manner, the cam frame 60 including, at the inner circumferentialsurface thereof, the second cam grooves 62 and the inner gear 64 can beformed by resin molding.

<6. Conclusion>

According to the present embodiment, the lens barrel 3 includes theouter frame 70, the optical system L disposed inside the outer frame 70,the zoom lever switch 73 (i.e., the zoom operation section) disposed onthe outer circumference of the outer frame 70, the focus lever switch 74(i.e., the focus operation section) disposed on the outer circumferenceof the outer frame 70, the electric zoom motor 52 and the cam frame 60(i.e., the zoom adjustment mechanism) which are configured to adjust themagnification of the optical system L in response to an output from thezoom lever switch 73, and the electric focus motor 53 and the fourthlens group frame 40 (i.e., the focus adjustment mechanism) which areconfigured to adjust the focus of the optical system L in response to anoutput from the focus lever switch 74. In the state in which the lensbarrel 3 is attached to the camera body 2 in the horizontal attitude, atleast part of the zoom lever switch 73 and at least part of the focuslever switch 74 are arranged in the arrangement region A formed of thefirst quadrant Q1 and the fourth quadrant Q4 of the lens barrel 3 asviewed from the side close to the object in the optical axis direction.

Regardless of whether the imaging apparatus 1 is in the horizontalattitude or the vertical attitude, the user can easily operate, with hisindex finger or thumb, the zoom lever switch 73 and the focus leverswitch 74 in the state in which the left hand is effortlessly placed onthe lens barrel 3. As a result, operability of the zoom lever switch 73and the focus lever switch 74 can be improved. Moreover, since the zoomlever switch 73 and the focus lever switch 74 are arranged in thecircumferential direction, the dimensions of the lens barrel 3 in theoptical axis direction can be reduced.

Various operation sections are provided for the camera body 2 and thelens barrel 3. The zoom lever switch 73 and the focus lever switch 74are operation sections which are often used upon shooting and which areoperated while the user is viewing an object image (i.e., operatedwithout looking the operation sections themselves). Thus, since the zoomlever switch 73 and the focus lever switch 74 are arranged as describedabove, operability and usability of the lens barrel 3 can be improved.

In the configuration in which the zoom lever switch 73 and the focuslever switch 74 which are for electrical driving are provided on theouter frame 70, the zoom lever switch 73 and the focus lever switch 74share the single flexible printed circuit board 81, and therefore thespace where the flexible printed circuit board 81 is laid can bereduced. Thus, the size of the lens barrel 3 can be reduced. Moreover,since the two switches 73, 74 share the same flexible printed circuitboard, the number of components can be reduced, and assembly propertiescan be improved.

At least part of one of the zoom lever switch 73 or the focus leverswitch 74 is disposed in the first quadrant Q1, and at least part of theother one of the zoom lever switch 73 or the focus lever switch 74 isdisposed in the fourth quadrant Q4. The operability can be improved insuch a manner that the zoom lever switch 73 and the focus lever switch74 are separated from each other to some extent. That is, if the zoomlever switch 73 and the focus lever switch 74 are too close to eachother, it is difficult to distinguish between the zoom lever switch 73and the focus lever switch 74 by the arrangement position. Moreover,there is a possibility that, when one of the switches should beoperated, the other switch is undesirably operated. Since one of theswitches is disposed in the first quadrant Q1, and the other switch isdisposed in the fourth quadrant Q4, the zoom lever switch 73 and thefocus lever switch 74 can be separated from each other with a moderatedistance. Thus, the user can easily distinguish between the zoom leverswitch 73 and the focus lever switch 74 by the arrangement position.Moreover, when one of the switches should be operated, undesirableoperation of the other switch can be reduced or prevented.

At least part of the zoom lever switch 73 and at least part of the focuslever switch 74 are arranged on a single circle about the optical axis.Thus, the operability of the zoom lever switch 73 and the focus leverswitch 74 can be improved, and the size of the lens barrel 3 can bereduced. That is, in the state in which the hand is placed on the outerframe 70, the thumb and the index finger are positioned on the singlecircle about the optical axis, i.e., positioned on the same circle.Since the zoom lever switch 73 and the focus lever switch 74 arearranged on the single circle about the optical axis, the zoom leverswitch 73 and the focus lever switch 74 can be easily operated with thethumb and the index finger. Moreover, since the zoom lever switch 73 andthe focus lever switch 74 are arranged on the single circle about theoptical axis, the position of the zoom lever switch 73 in the opticalaxis direction and the position of the focus lever switch 74 in theoptical axis direction are substantially coincident with each other.Thus, the dimensions of the outer frame 70 in the optical axis directioncan be reduced, and therefore the dimensions of the lens barrel 3 in theoptical axis direction can be reduced.

The zoom lever switch 73 and the focus lever switch 74 are configuredsuch that at least one of the shape, the texture, or the propertycontributing to a user's operation feeling varies between the zoom leverswitch 73 and the focus lever switch 74. Thus, the user can distinguishbetween the zoom lever switch 73 and the focus lever switch 74 withoutlooking the zoom lever switch 73 and the focus lever switch 74. As aresult, the operability of the zoom lever switch 73 and the focus leverswitch 74 can be improved.

For example, the lens barrel 3 includes the outer frame 70 and the zoomlever switch 73 and the focus lever switch 74 which are provided on theouter frame 70. The zoom lever switch 73 and the focus lever switch 74are configured to have the different shapes. Thus, the user candistinguish, without looking, between the zoom lever switch 73 and thefocus lever switch 74 by the feeling of touch or operation. As a result,the operability of the zoom lever switch 73 and the focus lever switch74 can be improved.

Specifically, the height H1a of the operating section 73 e of the zoomlever switch 73 and the height H1b of the operating section 74 e of thefocus lever switch 74 are different from each other, and therefore theshapes of the zoom lever switch 73 and the focus lever switch 74 aredifferent from each other.

The width W1a of the operating section 73 e of the zoom lever switch 73in the circumferential direction and the width W1b of the operatingsection 74 e of the focus lever switch 74 in the circumferentialdirection are different from each other, and therefore the shapes of thezoom lever switch 73 and the focus lever switch 74 are different fromeach other.

The width W2a of the zoom switch support 75 c of the zoom lever switch73 in the circumferential direction and the width W2b of the focusswitch support 75 d of the focus lever switch 74 in the circumferentialdirection are different from each other, and therefore the shapes of thezoom lever switch 73 and the focus lever switch 74 are different fromeach other.

As an example of the method for varying the shape between the zoom leverswitch 73 and the focus lever switch 74, one (in the present embodiment,the zoom lever switch 73) of the zoom lever switch 73 or the focus leverswitch 74 positioned on a counterclockwise side as viewed from the sideclose to the object in the arrangement region A is higher than the otherone of the zoom lever switch 73 or the focus lever switch 74 positionedon a clockwise side. In the state in which the left hand is placed on alower side of the lens barrel 3, the switch on the counterclockwise sideis positioned on a tip end side of the thumb, and the switch on theclockwise side is positioned on a base end side of the thumb. Since theswitch on the counterclockwise side is higher, erroneous operation ofthe switch on the clockwise side with the base of the thumb or theproximity thereof when the switch on the counterclockwise side isoperated with the thumb can be reduced or prevented.

Various operation sections are provided for the camera body 2 and thelens barrel 3. The zoom lever switch 73 and the focus lever switch 74are operation sections which are often used upon shooting and which areoperated while the user is viewing an object image (i.e., operatedwithout looking the operation sections themselves). Thus, since the zoomlever switch 73 and the focus lever switch 74 are formed in thedifferent shapes, the operability and usability of the lens barrel 3 canbe improved.

In the present embodiment, the lens barrel 3 includes the lens mount 90configured to determine the position of the lens barrel 3 relative tothe camera body 2 with the lens mount 90 contacting the camera body 2,the fixed frame (i.e., the outer frame 70) attached to the lens mount90, and the movable frame (i.e., the cam frame 60) housed so as to bemovable in the optical axis direction in the fixed frame. In the lensmount 90, the followings are provided: the attachment part (i.e., theattachment surface 92) to which the fixed frame is attached; and therecessed part 93 which is recessed toward the camera body 2 as comparedto the attachment part and into which the end part of the movable frameenters at least when the movable frame is positioned closest to the lensmount 90. The part 90A of the lens mount 90 where the attachment part isformed has a thickness greater than the part 90B of the lens mount 90where the recessed part 93 is formed.

Size reduction has been demanded for some types of lens barrels.However, if the size of a lens barrel is reduced, a movable range of amovable frame is limited. In order to reduce the size of the lens barreland ensure the movable range of the movable frame, it is necessary that,e.g., an essentially-required component is moved or deformed.

Since the configuration in which part of the lens mount 90 facing themovable frame is recessed and part of the movable frame enters such arecessed part is employed as in the foregoing, the movable range of themovable frame can be expanded.

In such a configuration, the part 90A of the attachment surface 92 ofthe lens mount 90 is formed so as to have the thickness T1 greater thanthe thickness T2 of the part 90B of the recessed part 93, therebymaintaining the strength of the lens mount 90. That is, the lens mount90 is a component required for attaching the lens barrel 3 to the camerabody, and a certain degree of strength is required for the lens mount90. The strength of the lens mount 90 may be lowered due to the recessedpart 93 of the lens mount 90. However, according to the foregoingconfiguration, even if the recessed part 93 is formed in the lens mount90, the thickness of the part 90A where the attachment surface 92 isformed can be increased to improve the strength of the lens mount 90.

Of the part 90B where the recessed part 93 is formed, part excludingpart of the part 90B facing the end part of the movable frame when themovable frame is positioned closest to the lens mount is formed with theprotrusion 93 a projecting relative to the part facing the end part ofthe movable frame. This improves the strength of the lens mount 90.

The protrusion 93 a is positioned inside the part facing the end part ofthe movable frame in the radial direction. Thick parts are formed insideand outside the recessed part 93 in the radial direction. According tothis configuration, even if the recessed part 93 is formed in the lensmount 90, the strength of the lens mount 90 can be improved.

According to the present embodiment, the lens barrel 3 includes thecylindrical cam frame 60 formed, at the inner circumferential surfacethereof, with the second cam grooves 62 each extending in thepredetermined pattern, and the inner gear 64 inwardly protruding in theradial direction and extending in the circumferential direction; and thesecond lens group frame 20 including the base 21 a configured to holdthe first to sixth lenses L4-L6 inside the cam frame 60, the extensions21 b each extending from the outer circumferential end part of the base21 a in the optical axis direction, and the cam pins 22 each outwardlyprotruding from the tip end part of a corresponding one of theextensions 21 b and fitted into a corresponding one of the second camgrooves 62. In the extension 21 b, the stepped part 21 c inwardlyrecessed in the radial direction as compared to the tooth tip 64 a ofthe inner gear 64 is formed so as to, when each cam pin 22 movesaccording to a corresponding one of the second cam grooves 62, overlapwith the inner gear 64 as viewed in the radial direction and so as notto overlap with the tooth tip 64 a of the inner gear 64 as viewed in thecircumferential direction.

For example, in each of lens barrels of Japanese Unexamined PatentPublication No. 2010-186192 (hereinafter referred to as “Patent Document1”) and Japanese Unexamined Patent Publication No. 2010-204563(hereinafter referred to as “Patent Document 2”), a gear part is formedat a rear end of an outer circumferential surface of a drive frameformed with cam grooves. The gear part of the drive frame is engagedwith a drive gear of a fixed frame. In such a state, when a zoom motoris operated, drive force of the zoom motor is transmitted to the gearpart of the drive frame through the drive gear. The drive frame isrotatably driven. While rotating relative to the fixed frame, the driveframe is moving in an optical axis direction. As a result, a lens(es) ismoving in the optical axis direction.

However, in each of the lens barrels of Patent Documents 1 and 2, thegear is formed at the outer circumferential surface of the drive frame,and therefore a drive gear of the zoom motor should be disposed outsidethe drive frame in a radial direction. In this configuration, the outerdiameter of the lens barrel increases, and it is difficult to reduce thesize of the lens barrel.

For such a reason, it is necessary to devise arrangement of a gear of acam frame to provide a lens barrel having a reduced size.

According to the foregoing configuration, since the inner gear 64 isformed at the inner circumferential surface of the cam frame 60, thesize of the lens barrel 3 can be reduced as compared to the case wherethe gear is formed at the outer circumferential surface of the cam frame60. Moreover, since the stepped part 21 c is formed in the extension 21b of the second lens group frame 20, the second lens group frame 20 cansmoothly move in the optical axis direction without contact between thetooth tip 64 a of the inner gear 64 and the extension 21 b of the secondlens group frame 20 when each cam pin 22 moves according to acorresponding one of the second cam grooves 62.

The mold for forming the inner circumferential surface of the cam frame60 is divided into the first mold 95 configured to form part of theinner gear 64 and the cam pin insertion part 62 d, the second mold 96configured to form the remaining part of the inner gear 64 and part ofthe second cam groove 62 positioned above the inner gear 64, the thirdmold 97 configured to form the second cam groove 62 positioned below theinner gear 64, and the fourth mold 98 configured to form the second camgroove 62 apart from the inner gear 64 in the circumferential direction.

Since the tooth edges of the inner gear 64 extend parallel to theoptical axis, the first mold 95 can be moved upward and removed, and thesecond to fourth molds 96-98 are obliquely downwardly moved toward theinside in the radial direction and removed. The cam frame 60 including,at the inner circumferential surface thereof, the second cam grooves 62and the inner gear 64 can be formed by resin molding.

<<Other Embodiments>>

As described above, the embodiment has been described as an exampletechnique disclosed in the present application. However, the techniqueaccording to the present disclosure is not limited to the foregoingembodiment, but is also applicable to those where modifications,substitutions, additions, and omissions are made. In addition, elementsdescribed in the foregoing embodiment may be combined to provide adifferent embodiment.

The foregoing embodiment may have the following configurations.

That is, the configuration of the lens barrel 3 is not limited to thatof the foregoing embodiment. In other words, as long as the lens barrelis configured to electrically drive the zoom lens(es) and the focuslens(es), any types of lens barrels can be employed.

The lens barrel 3 is the interchangeable lens barrel detachably attachedto the camera body 2, but is not limited to such a barrel. The lensbarrel 3 may be attached to the camera body 2 so as not to be detachedfrom the camera body 2. For example, the lens barrel 3 may be a lensbarrel of a compact camera.

As long as the camera body 2 is a device having an imaging function, anytypes of devices can be employed. That is, the camera body 2 may be,e.g., a still camera, a video camera, or a mobile phone or a mobileterminal including a camera section.

In the foregoing embodiment, the zoom lever switch 73 is disposed in thefirst quadrant Q1, and the focus lever switch 74 is disposed in thefourth quadrant Q4. However, the present disclosure is not limited tosuch a configuration. The zoom lever switch 73 may be disposed in thefourth quadrant Q4, and the focus lever switch 74 may be disposed in thefirst quadrant Q1. Alternatively, both of the zoom lever switch 73 andthe focus lever switch 74 may be arranged in the first quadrant Q1 orthe fourth quadrant Q4.

In the foregoing embodiment, the zoom lever switch 73 and the focuslever switch 74 are formed in the different shapes in such a manner thatthe heights H of the operating sections 73 e, 74 e vary from each other,that the widths W1 of the operating sections 73 e, 74 e in thecircumferential direction vary from each other, and that the widths W2of the switch supports 75 c, 75 d vary from each other. However, thepresent disclosure is not limited to such a configuration. Any of theforegoing dimensions may vary between the operation sections.Alternatively, other configurations may vary between the operationsections. As still another alternative, any of the foregoing differencesmay be optionally combined together. For example, the height H2a of theoperating section 73 e from the zoom switch support 75 c and the heightH2b of the operating section 74 e from the focus switch support 75 d maybe different from each other. The widths of the operating sections 73 e,74 e in the optical axis direction may be different from each other. Theheight of the zoom switch support 75 c and the height of the focusswitch support 75 d may different from each other. The areas of the tipend surfaces (i.e., operation surfaces at which the user operates theoperating sections 73 e, 74 e) of the operating sections 73 e, 74 e maydifferent from each other. The shapes of the tip end surfaces of theoperating sections 73 e, 74 e may different from each other. Althoughthe tip end surfaces of the operating sections 73 e, 74 e are in asubstantially rectangular shape in the foregoing embodiment, any of thetip end surfaces may be in, e.g., a substantially circular shape or asubstantially triangular shape. Although knurls are formed at the tipend surfaces of the operating sections 73 e, 74 e in the foregoingembodiment, different surface treatments may be applied to the operatingsections 73 e, 74 e. For example, the types of knurling may vary betweenthe operating sections 73 e, 74 e, or different surface treatments otherthan knurling may be applied to the operating sections 73 e, 74 e.Alternatively, a surface treatment may be applied to one of the tip endsurfaces of the operating sections 73 e, 74 e, and no surface treatmentmay be applied to the other tip end surface of the operating sections 73e, 74 e.

In the foregoing embodiment, the zoom lever switch 73 and the focuslever switch 74 are formed in the different shapes. However, thematerials of the zoom lever switch 73 and the focus lever switch 74 maybe different from each other. For example, the materials of theoperating sections 73 e, 74 e may be different from each other. One ofthe operation sections may be made of, e.g., metal, and the otheroperation section may be made of, e.g., resin. Alternatively, one of theoperation sections may be made of resin plated with metal, and the otheroperation section may be made of resin which is not plated with metal.As still another alternative, one of the operation sections may be madeof resin coated with rubber, and the other operation section may be madeof resin which is not coated with rubber. As just described, thematerials themselves of the operating sections 73 e, 74 e may bedifferent from each other, or the surface textures of the operatingsections 73 e, 74 e may vary by plating or coating.

Operation force may be different between the zoom lever switch 73 andthe focus lever switch 74. For example, the spring constant of thespring 73 c of the zoom lever switch 73 and the spring constant of thespring 74 c of the focus lever switch 74 may be different from eachother. In this case, the operation force of the focus lever switch 74 issmaller than that of the zoom lever switch 73, thereby more preciselyadjusting the focus of the optical system L as compared to themagnification of the optical system L. Note that a method for varyingoperation force is not limited to the method by which the springconstants of the springs 73 c, 74 c vary from each other. The slideresistance of the lever 73 a and the slide resistance of the lever 74 amay be different from each other.

An operation method may vary between the zoom lever switch 73 and thefocus lever switch 74. For example, a switch type may be different.Specifically, one of the switches may be a lever switch, and the otherswitch may be a seesaw switch. Alternatively, switches (e.g., pushswitches) other than the foregoing switches may be used. As stillanother alternative, in the case where both switches are lever switches,one of the switches may be configured to be slidable with the switchbeing pushed in, and the other switch may be configured to be slidablewithout the switch being pushed in. The operation directions (i.e.,directions in which the switches move during operation thereof) of bothswitches may be different from each other. That is, although both of thezoom lever switch 73 and the focus lever switch 74 are configured toslide in the circumferential direction in the foregoing embodiment, thezoom lever switch 73 and the focus lever switch 74 may be configuredsuch that one of the zoom lever switch 73 or the focus lever switch 74slides in the optical axis direction. In the case of the seesawswitches, a swing shaft of one of the switches may be coincident withthe optical axis direction, a swing shaft of the other switch may becoincident with the circumferential direction (more precisely, atangential direction).

The levers 73 a, 74 a of the zoom lever switch 73 and the focus leverswitch 74 have been mainly described above. The shapes or materials ofthe switch supports 75 c, 75 d may be vary from each other in thesimilar manner.

As just described, the shapes of the zoom lever switch 73 and the focuslever switch 74 are not necessarily different from each other, and anyone of the material, operation force, or operation method may bedifferent between the zoom lever switch 73 and the focus lever switch74. Note that all or some of the shape, material, operation force, andoperation method may be different between the zoom lever switch 73 andthe focus lever switch 74.

For example, either one of two switches may be larger or smaller in asize relationship, and may be higher or lower in a height relationship.

In the foregoing embodiment, two operation sections provided on thebarrel body 3A are the zoom lever switch 73 and the focus lever switch74, but are not limited to the zoom lever switch 73 and the focus leverswitch 74. For example, the operation sections may be diaphragmoperation switches each configured to adjust a diaphragm. The number ofoperation sections provided on the barrel body 3A is not limited to two,and three or more operation sections may be provided. In such a case, inthe configuration in which the operation sections are arranged in thearrangement region A, all of the operation sections are preferablyarranged in the arrangement region A, but at least two of the operationsections may be arranged in the arrangement region A. Of all of theoperation sections, at least two operation sections which are often usedupon imaging are, in this case, preferably arranged in the arrangementregion A. In the configuration in which the shape, the material, theoperation force, and/or the operation method vary among the operationsections, they preferably vary among all of the operation sections, butmay vary between at least two of the operation sections. In such a case,the shape, the material, the operation force, and/or the operationmethod preferably vary between at least two of the operation sectionsoperated upon imaging, and in particular between at least two of theoperation sections operated while the user is viewing an object image.

The configuration in which the end part of the cam frame 60 enters therecessed part 93 of the lens mount 90 is employed, but the presentdisclosure is not limited to such a configuration. Depending on theconfiguration of the lens barrel, the movable frame, e.g., the firstlens group frame 10, other than the cam frame 60 may enter the recessedpart 93. Moreover, the number of movable frames entering the recessedpart 93 is not limited to one, and a plurality of movable frames mayenter the recessed part 93.

As long as the stepped part 21 c formed in the extension 21 b of thesecond lens group frame 20 can avoid contact with the inner gear 64, theshape of the stepped part 21 c is not limited to that of the foregoingembodiment.

Three extensions 21 b of the second lens group frame 20 are arranged soas to be apart from each other in the circumferential direction of thebase 21 a, but the number of extensions 21 b are not limited to three.Moreover, the stepped part 21 c is formed in one of the three extensions21 b, but the present disclosure is not limited to such a configuration.For example, the stepped part 21 c may be formed in each extensions 21b.

The extension 21 b of the second lens group frame 20 may extend, at theposition inside the tooth tip 64 a of the inner gear 64 in the radialdirection, from the base 21 a in the optical axis direction so as not tooverlap with the tooth tip 64 a of the inner gear 64 as viewed in thecircumferential direction. In such a configuration, even if no steppedpart 21 c is formed in the extension 21 b, contact with the inner gear64 can be avoided. The present disclosure is not limited to theconfiguration in which one of the three extensions 21 b extends, withoutthe stepped part, from the base 21 a in the optical axis direction atthe position inside the tooth tip 64 a of the inner gear 64 in theradial direction. For example, all of the extensions 21 b may have thesimilar configuration.

The positions at which the first to fourth molds 95-98 are separatedfrom each other and the number of the first to fourth separate molds95-98 have been described as one example, and are not limited to thoseof the foregoing embodiment. For example, only part of the inner gear 64may be formed using the first mold 95, and the cam pin insertion part 62d, the remaining part of the inner gear 64, and the second cam groove 62positioned above the inner gear 64 may be formed using the second mold96.

A right end edge (i.e., a right end edge of the cam groove molding part96 a) of the second circumferential straight part 62 c of the second camgroove 62 positioned below the inner gear 64 may be a separation line atwhich the first mold 95 and the second mold 96 are separated from eachother in the circumferential direction. That is, part of the inner gear64 positioned on the right side relative to such a separation line isformed using the first mold 95. The remaining part of the inner gear 64positioned on the left side relative to the separation line is formedusing the second mold 96. In such a state, a right end edge (or aposition slightly apart from the right end edge of the inner gear 64) ofthe inner gear 64 formed using the first mold 95 may be a separationline at which the first mold 95 and the third mold 97 are separated fromeach other in the circumferential direction. Moreover, an upper end edgeof the inner gear 64 formed using the first mold 95 may be a separationline at which the first mold 95 and the second mold 96 are separatedfrom each other in the optical axis direction and the first mold 95 andthe third mold 97 are separated from each other in the optical axisdirection.

The foregoing embodiments have been set forth merely for the purpose ofpreferred examples in nature, and are not intended to limit the scope,applications, and use of the invention.

As described above, the technique disclosed herein is useful for a lensbarrel.

Various embodiments have been described above as example techniques ofthe present disclosure, in which the attached drawings and the detaileddescription are provided.

As such, elements illustrated in the attached drawings or the detaileddescription may include not only essential elements for solving theproblem, but also non-essential elements for solving the problem inorder to illustrate such techniques. Thus, the mere fact that thosenon-essential elements are shown in the attached drawings or thedetailed description should not be interpreted as requiring that suchelements be essential.

Since the embodiments described above are intended to illustrate thetechniques in the present disclosure, it is intended by the followingclaims to claim any and all modifications, substitutions, additions, andomissions that fall within the proper scope of the claims appropriatelyinterpreted in accordance with the doctrine of equivalents and otherapplicable judicial doctrines.

What is claimed is:
 1. A lens barrel in which a lens is movable in anoptical axis direction, comprising: a cylindrical cam frame formed, atan inner circumferential surface thereof, with a cam groove extending ina predetermined pattern, and an inner gear inwardly protruding in aradial direction and extending in a circumferential direction; and alens frame including a base configured to hold the lens inside the camframe, an extension extending from the base in the optical axisdirection, and a cam pin outwardly protruding from a tip end part of theextension in the radial direction and fitted into the cam groove,wherein a stepped part which, when the cam pin moves according to thecam groove, overlaps with the inner gear as viewed in the radialdirection and is recessed toward an inside in the radial direction ascompared to a tooth tip of the inner gear so as not to contact the innergear is provided in the extension.
 2. The lens barrel of claim 1,wherein the extension includes a plurality of extensions arranged so asto be apart from each other in the circumferential direction of thebase, and the stepped part is formed in at least one of the extensions.